BP and federal officials still have not decided how they will proceed with a final kill of the runaway Gulf of Mexico well, National Incident Commander Thad Allen said in a press briefing in Florida this morning.

"We continue to assess the condition of the well," said Allen, who could not say when a final decision will be made.

Allen also said the blow-out preventer that was being used in the drilling of a second relief well is being removed for use on the Macondo well.

BP has long planned to pump cement through a relief well into the bottom of the well in a final attempt to kill it. But over the past week, officials have become concerned that pumping cement in through the bottom could put too much pressure on a sealed outer layer of the well.

"There wasn't a plan in place (to deal with pressure in the well) because this has never been done before," Allen said Wednesday.

Two options are being considered to relieve the pressure.

One option is to remove the existing capping stack and blow-out preventer and put a new blow-out preventer on the Macondo well. The blow-out preventer that had been in use on the second relief well could be used for that purpose.

A second option involves developing a pressure relief mechanism in the capping stack.

Once federal officials and BP decide how to deal with pressure in the well, Allen said he will direct drilling of the primary relief well to resume.